Daniil Kvyat says the gap between Honda and the other engine manufacturers on the grid is now "minimal".
The Japanese manufacturer, which supplies engines to both Red Bull teams, introduced its 'Spec 4' engine at Spa.
Toro Rosso boss Franz Tost said at Monza: "With the Spec 4 engine, I don't think that we have any more disadvantage."
When asked about his boss's comments, Russian driver Kvyat said: "Yes, if there is a difference, then it is minimal and difficult to calculate.
"Honda is doing an excellent job.
"We look especially good in the races, and we hope that in the future we will be able to improve in qualifying.
"But Sunday is the main day of the weekend, and Honda has made very good progress," he added.
